1. Field of the Invention
The present invention relates to a wear-resistive housing for a portable electronic device, and more particularly to a low cost wear-resistive housing for a portable electronic device, which contains a hardness-improving additive. In addition to the wear-resistive characteristic, the housing may contain other additives to provide effects or characteristics such as improved surface smoothness for scratch protection, anti-bacterium effect, negative ion generation, anti-ultra-violet ray (referred to hereinafter as “anti-UV”) effect, anti-electromagnetic interference (referred to hereinafter as “anti-EMI”) effect, flame retardant effect, odor and humidity absorption effect, improved insulation, far infrared ray (referred to hereinafter as “far IR”) generation, etc.
2. Description of the Related Art
Portable electronic devices such as mobile phones, PDA's (Personal Digital Assistants), digital cameras, notebook computers, and so on, have almost become necessaries in our daily life. However, there is a disadvantage common to these portable electronic devices, that is, the housing of a portable electronic device is easily and often worn to lose the elegance its original design.
Due to cost concern, the housing of a portable electronic device is often made of injection molding plastic materials such as PC (polycarbonate) or ABS (Acrylonitrile Butadiene Styrene). To provide different colors in the appearance, another approach is to coat the housing with a coating made of a material such as epoxy resin, PU resin (polyurethane resin), or PMMA resin (polymethyl methacrylate resin).
Because the housing of a portable electronic device is often made of a plastic or resin material, its hardness is not satisfactory. A housing made of PC or ABS has a hardness generally in a range of 2H-2.5H, which can not achieve the desired wear-resistive effect. This is why we often see a mobile phone with worn traces.
The aforementioned disadvantage has long been known by those in this art. One possible solution thereto is to make the housing by magnesium-aluminum alloy. This may improve the hardness of the housing to 5H, but the material cost is 20-30 times of the cost of the plastic or resin material, which is of course undesired. Another possible solution is to mix plastic and/or resin materials to improve hardness, but the resultant hardness may at most be improved to about 2.5H-3H, far below what is desired. Until the present invention, there has not been any satisfactory solution to improve hardness of a housing made of a plastic or resin material, or a mixture material of plastic(s) and/or resin(s).